Hydroconversion Multi-Metallic Catalysts and Method for Making Thereof

ABSTRACT

A self-supported mixed metal sulfide (MMS) catalyst for hydrotreating hydrocarbon feedstock is disclosed. The self-supported MMS catalyst is characterized by an HDN reaction rate constant of at least 100 g feed hr −1  g catalyst −1  assuming first order kinetics, and an HDS reaction rate constant of at least 550 g feed hr −1  g catalyst −1  assuming first order kinetics in hydrotreating of a Heavy Coker Gas Oil as a feedstock with properties indicated in Table A and at given process conditions as indicated in Table E. In one embodiment, the catalyst is characterized as having a multi-phased structure comprising five phases: a molybdenum sulfide phase, a tungsten sulfide phase, a molybdenum tungsten sulfide phase, an active nickel phase, and a nickel sulfide phase.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit under 35 USC 119 of U.S. ProvisionalPatent Application Nos. 61/697,063 with a filing date of Sep. 5, 2012and 61/801,683 with a filing date of Mar. 15, 2013.

TECHNICAL FIELD

The invention relates generally to a self-supported mixed metal sulfide(MMS) catalyst for use in hydroprocessing, processes for preparing thecatalyst, and hydroconversion processes employing the multi-metalliccatalyst.

BACKGROUND

In the crude oil market, there is a premium for refineries to processfeeds derived from more refractory crudes into high value finishedproducts. These refractory feeds are characterized by a higher densityresulting from an increased fraction of aromatic compounds with a lowhydrogen content. Therefore, these feeds require deeper hydrogenation(more extensive saturation of aromatic compounds) to produce fuels thatmeet specifications, such as viscosity, cold flow properties, cetaneindex, smoke point, emission requirements. The volumetric productivityof such a process provides higher benefits to refineries that deployhydrogenation (HYD) catalysts powerful enough to meet the requiredhydrogenation activity.

Although hydrogenation is an important aspect of refining high densityfeeds, deep hydrogenation catalysts need to deliver more than maximizingthe increase in volume between feed and refined products. In the wake ofEuropean environmental legislation, there is a global trend towards morestringent legislation that mandates environmentally friendlytransportation fuels. An example is the mandate that all diesel producedin and imported into the US will have to be ultra-low-sulfur diesel(ULSD) as of Dec. 1, 2014. This change to transportation fuels with thelow sulfur content allows for application of newer emission controltechnologies that should substantially lower emissions of particulatematter from diesel engines. Environmental mandates to removecontaminants like sulfur from refined oil products implies a need forcatalysts which combine a deep hydrogenation (HYD) capability with adeep hydrodesulfurization (HDS) activity. This deep hydrodesulfurizationactivity is particularly important in refining high-density feed stocks,because a higher density typically implies a higher concentration ofcontaminants such as organic sulfur and nitrogen molecules, as well asmetals and asphaltenes (i.e. multi-ring based aromatic compounds with alow solubility even in the most aromatic solvents).

Deep hydrodesulfurization is accomplished most efficiently through acombination of: 1) hydrogenation (HYD), which releases sulfur atomsafter saturating the ring structure of parent aromatic compounds and 2)hydrogenolysis (HYL), which breaks the bond between a sulfur atom andthe carbon atom(s) in the sulfur containing molecule , such as aromaticring compounds. This implies that optimum catalysts for the deephydrogenation of high-density feed stocks are expected to exhibit anappropriate balance between hydrogenation and hydrogenolysis functions.Catalysts that are suitable for hydroprocessing (e.g.hydrodesulfurization and hydrodenitrogenation) generally comprisemolybdenum or tungsten sulfide or sulfocarbide, in combination with anelement such as cobalt, nickel, iron, or a combination of thereof.Attempts have been made to modify the morphology of hydroprocessingcatalysts to provide ways to control their activity and selectivity. Forexample, U.S. Pat. No. 4,528,089 discloses that catalysts prepared fromcarbon-containing catalyst precursors are more active than catalystsprepared from sulfide precursors without organic groups.

Considerable experimental and modeling efforts have been underway tobetter understand complex metal sulfide catalysts, including factorsthat control metal sulfide morphology. U.S. Pat. Nos. 7,591,942 and7,544,632 demonstrate that sulfiding a self-supported multi-metalliccatalyst in the presence of a surfactant amine gives a catalystcomprising stacked layers of molybdenum or tungsten sulfide with areduced number of layers in stacks. A lower number of layers in stacksimplies the presence of smaller crystals of molybdenum, tungsten ormolybdenum tungsten sulfides, which can result in larger surface areasavailable for catalysis.

The saturation of aromatic compounds in distillate fractions, e.g.vacuum gas oil, heavy coker gas oil or diesel fuel has also drawnattention of researchers. A high aromatic content is associated withhigh density, poor fuel quality, low cetane numbers of diesel fuel andlow smoke point values of jet fuel. High hydrodenitrogenation (HDN)activity is typically associated with aromatic saturation activity ofnickel tungsten sulfides catalysts; while high hydrodesulfurization(HDS) activity associates with high hydrogenolysis activity of cobaltmolybdenum sulfide catalysts.

There is still a need for improved catalysts with improved catalyticactivity and resistance towards deactivation, specificallyself-supported mixed metal sulfide catalysts for use in thehydroprocessing of lower grade, more refractory hydrocarbon feeds,capable of generating low aromatic products meeting new emissionrequirements. There is also a need for a better understanding ofstructure—performance relationships for these catalysts to design nextgeneration of highly active self-supported catalysts for use inhydroprocessing.

SUMMARY

In one aspect, the invention relates to a self-supported mixed metalsulfide (MMS) catalyst consisting essentially of nickel sulfide andtungsten sulfide, wherein the catalyst contains Ni:W in a mole ratio of1:3 to 4:1, on a transition metal basis. In one embodiment, the catalystfurther comprises a metal promoter selected from Mo, Nb, Ti, andmixtures thereof, wherein the metal promoter is present in an amount ofless 1% (mole).

In a second aspect, the invention relates to a MMS catalyst consistingessentially of molybdenum sulfide and tungsten sulfide, wherein thecatalyst contains at least 0.1 mol % of Mo and at least 0.1 mol % of W,on a transition metal basis. In one embodiment, the catalyst ischaracterized as having an HDS reaction rate constant of at least 10%higher than that of a catalyst comprising molybdenum sulfide alone or acatalyst comprising tungsten sulfide alone, when compared on same metalmolar basis in hydrotreating a Heavy Coker Gas Oil as a feedstock atidentical process conditions as indicated in Table E.

In a third aspect, the invention relates to a MMS catalyst comprisingmolybdenum sulfide, nickel sulfide, and tungsten sulfide, wherein thecatalyst is characterized by an HDN reaction rate constant of at least100 g feed hr⁻¹ g catalyst⁻¹ assuming first order kinetics, and an HDSreaction rate constant of at least 550 g feed hr⁻¹ g catalyst⁻¹ assumingfirst order kinetics in hydrotreating of a Heavy Coker Gas Oil as afeedstock with properties indicated in Table A and at given processconditions as indicated in Table E. In one embodiment, the catalyst ischaracterized by an HDN reaction rate constant of at least 4 hr⁻¹assuming first order kinetics, and an HDS reaction rate constant of atleast 5 hr⁻¹ assuming first order kinetics in hydrotreating of a HeavyVacuum Gas Oil as a feedstock with properties indicated in Table B andat the steady state process conditions as indicated in Table F. Inanother embodiment, the catalyst is characterized by an HYD reactionrate constant and an HYL reaction rate constant of at least 10% higherthan the rate constants of a catalyst comprising nickel sulfide andmolybdenum sulfide, or a catalyst comprising nickel sulfide and tungstensulfide, when compared on same metal molar basis in hydrotreating adiphenylether as a feedstock at identical process conditions asindicated in Table C.

In a fourth aspect, the invention relates to a MMS catalyst comprisingmolybdenum sulfide, nickel sulfide, and tungsten sulfide, and whereinthe catalyst is characterized as having molar ratios of metal componentsNi:Mo:W in a region defined by five points ABCDE of a ternary phasediagram, and wherein the five points ABCDE are defined as: A (Ni=0.72,Mo=0.00, W=0.25), B (Ni=0.25, Mo=0.00, W=0.75), C (Ni=0.25, Mo=0.25,W=0.50), D (Ni=0.60, Mo=0.25, W=0.15), E (Ni=0.72, Mo=0.13, W=0.15). Inone embodiment, the catalyst is characterized having a molar ratio ofmetal components Ni:Mo:W in a range of: 0.33<=Ni/(W+Mo)≦2.57;0.00≦Mo/(Ni+W)≦0.33; and 0.18≦W/(Ni+Mo)≦3.00.

In a fifth aspect, the invention relates to a MMS catalyst comprisingmolybdenum sulfide, nickel sulfide, and tungsten sulfide, wherein thecatalyst is characterized as having a multi-phased structure comprisingfive phases: a molybdenum sulfide phase, a tungsten sulfide phase, amolybdenum tungsten sulfide phase, an active nickel phase, and a nickelsulfide phase. In one embodiment, the molybdenum tungsten sulfide phasecomprises at least a layer, wherein the at least a layer contains atleast one of: a) molybdenum sulfide and tungsten sulfide; b) tungstenisomorphously substituted into molybdenum sulfide as individual atoms oras tungsten sulfide domains; c) molybdenum isomorphously substitutedinto tungsten sulfide as individual atoms or as molybdenum sulfidedomains; and d) mixtures thereof

In a sixth aspect, the invention relates to a MMS catalyst comprisingmolybdenum (Mo) sulfide, tungsten (W) sulfide, and nickel (Ni) sulfide,wherein the catalyst has a BET surface area of at least 20 m²/g and apore volume of at least 0.05 cm³/g. In one embodiment, the catalyst hasa BET surface area of at least 30 m²/g.

In a seventh aspect, the invention relates to a method for making a MMScatalyst, the method comprising mixing a sufficient amount of a nickel(Ni) metal precursor, a sufficient amount of a molybdenum (Mo) metalprecursor, and a sufficient amount of a tungsten (W) metal precursor toproduce a catalyst precursor having a molar ratio Ni:Mo:W in relativeproportions defined by a region of a ternary phase diagram showingtransition metal elemental composition in terms of nickel, molybdenum,and tungsten mol-%, wherein the region is defined by five points ABCDEand wherein the five points are: A (Ni=0.72, Mo=0.00, W=0.28), B(Ni=0.55, Mo=0.00, W=0.45), C (Ni=0.48, Mo=0.14, W=0.38), D (Ni=0.48,Mo=0.20, W=0.33), E (Ni=0.62, Mo=0.14, W=0.24); and sulfiding thecatalyst precursor under conditions sufficient to convert the catalystprecursor into a sulfide catalyst.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a ternary phase diagram showing contents of nickel,molybdenum, and tungsten as atomic % on 100% metal basis inself-supported catalysts optimized to have significantly enhanced HYL,HYD, HDS and HDN activities, as compared to multi-metallic catalysts ofthe prior art.

FIG. 2 is a ternary phase diagram showing contents of nickel andtungsten as atomic % on 100% metal basis in self-supported catalysts,optimized to have significantly enhanced HYD and HDN activities.

FIG. 3 is a ternary phase diagram showing contents of molybdenum andtungsten as atomic % on 100% metal basis in self-supported catalysts,optimized to have significantly enhanced HYL and HDS activities.

FIG. 4 is an image showing the XRD pattern (counts per second as afunction of degrees 2 theta) of a spent catalyst having the compositionwithin the optimum compositional range of 50 mol-% Ni, 25 mol-% Mo and25 mol-% W.

FIG. 5 is an image showing the XRD pattern (counts per second as afunction of degrees 2 theta) of another spent catalyst having thecomposition within the optimum compositional range of 55 mol-% Ni, 14mol-% Mo and 31 mol-% W.

FIG. 6 is an image showing the XRD pattern (counts per second as afunction of degree 2 theta) of a spent catalyst with composition of 10mol-% Ni, 45 mol-% Mo and 45 mol-% W.

FIG. 7 is a TEM image showing crystalline Ni₉S₈ and Ni₃S₂ phases in thespent catalyst with a composition of 50 mol-% Ni, 25 mol-% Mo and 25mol-% W.

FIG. 8 is a TEM image showing nano-particles of nickel sulfide in thespent catalyst with composition of 50 mol-% Ni, 25 mol-% Mo and 25 mol-%W.

FIG. 9 is a TEM image of the spent catalyst with a composition of 50mol-% Ni, 25 mol-% Mo and 25 mol-% W, showing curved multi-layerstructure of molybdenum sulfide and tungsten sulfide particles.

FIG. 10 is a TEM image of a spent catalyst with composition of 10 mol-%Ni, 45 mol-% Mo and 45 mol-% W.

FIG. 11 is a graph showing Ni and W surface concentrations as determinedby XPS for different catalysts.

FIG. 12 is a graph showing BET surface areas of freshly prepared andspent catalysts (after hydrotreating of coker gas oil feed).

FIG. 13 is a graph comparing pore volumes of freshly prepared and spentcatalysts (after hydrotreating of coker gas oil feed for at least 0.5hr).

FIG. 14 is a pictorial representation of a surface structure of aself-supported catalyst in the optimum compositional range consisting of50 mol-% Ni, 25 mol-% Mo and 25 mol-% W.

FIG. 15 is a pictorial representation of surface structure of acomparative self-supported catalyst outside the optimum compositionalrange with 10 mol-% Ni, 45 mol-% Mo and 45 mol-% W.

FIG. 16 is a pictorial representation of a TEM, showing 0.5-3 nm NiS_(x)droplets on WMo_((1-z))S₂ layers.

FIG. 17 is a pictorial representation of surface structure of themolybdenum tungsten sulfide phase in any form of: 1) intralayer atomicmixture; 2) inter-layer mixture of tungsten sulfide and molybdenumsulfide; and 3) a mixture of individual domains of tungsten sulfide andmolybdenum sulfide.

DETAILED DESCRIPTION

The following terms will be used throughout the specification and willhave the following meanings unless otherwise indicated.

References to terms such as “edge,” “basal,” “rim,” and “layer,” can befound in “Structural Studies of Catalytically Stabilized IndustrialHydrotreating Catalysts,” by De la Rosa et al., Science HighlightNovember 2004.

Reference to “slab” refers to the crystal morphology of single particlesor particle agglomerates of nickel sulfide.

The Periodic Table referred to herein is the Table approved by IUPAC andthe U.S. National Bureau of Standards. An example is the Periodic Tableof the Elements by Los Alamos National Laboratory's Chemistry Divisionof October 2001.

“Self-supported” may be used interchangeably with “bulk catalyst” or“unsupported catalyst,” meaning that the catalyst composition is not ofthe conventional catalyst form which consists of a catalyst deposited ona preformed shaped catalyst support. In one embodiment, theself-supported catalyst is formed through precipitation. In anotherembodiment, the self-supported catalyst has a binder incorporated intothe catalyst composition.

In yet another embodiment, the self-supported catalyst is formed frommetal compounds and without any binder.

“One or more of” or “at least one of” when used to preface severalelements or classes of elements such as X, Y and Z or X₁-X_(n), Y₁-Y_(n)and Z₁-Z_(n), is intended to refer to a single element selected from Xor Y or Z, a combination of elements selected from the same common class(such as X₁ and X₂), as well as a combination of elements selected fromdifferent classes (such as X₁, Y₂ and Z_(n)).

“Molybdenum sulfide” refers to MoS_(2+e) where e has a value between 0and 1, and in one embodiment further comprises carbide, nitride, and/orsulfocarbide domains. MoS₂ as used herein is by way of exemplificationfor molybdenum sulfide or MoS_(2+e) in general, and is not intended toexclude any molybdenum sulfide not represented by the formula.

“Tungsten sulfide” refers to WS_(2+e) where e may have a value between 0and 1, and in one embodiment further comprises carbide, nitride, and/orsulfocarbide as well as oxysulfide domains. WS₂as used herein is by wayof exemplification for tungsten sulfide or WS_(2+e) in general, and isnot intended to exclude any tungsten sulfide not represented by theformula.

“Heavy Coker Gas Oil” refers to a coker gas oil feedstock with thefollowing properties: API of 31.4 (0.8686 g/ml); C of 85.7 wt %; H of12.246 wt %; N of 1986 ppm; S of 1.6680 wt. %; Bromine number of 37;total aromatics of 35.2 wt. %, distributed as mono-aromatics of 23.3 wt.% and poly-aromatics of 11.9 wt. %, with a boiling point distribution asshown in Table A below.

TABLE A (Simulated Distillation) Wt. % (° F.) 0.5 323 5 416 10 443 30493 50 527 70 557 90 588 95 601 99 624 99.5 629

“Heavy Vacuum Gas Oil” refers to a vacuum gas oil feedstock with thefollowing properties: API of 21.1 (0.9273 g/ml); C of 84.89%; H of11.951%; N of 974 ppm; S of 2.335 wt. %; viscosity at 100° F. of 9.357cst, with a boiling point distribution as shown in Table B below.

TABLE B (Simulated Distillation) Wt % ° F. 0.5 627 5 702 10 737 30 80550 855 70 907 90 975 95 1002 99 1049 99.5 1063

Hydrogenolysis (HYL) reaction conditions of diphenylether (model feed)are shown in the Table C below, and also detailed in the Experimentsection:

TABLE C Reactor 1 L batch autoclave Catalyst precursor Organo metalliccompounds of nickel, molybdenum and tungsten Sulfiding agent DMDS, CS₂Feed diphenylether Solvent hexadecane Atomsphere H₂ Stir rate 750 rpmReaction Temperature ramping RT → 382° C. in 2 hr conditions Pressure1800 psig Temperature 382° C. (720° F.) Residence time 0.5 hr QuenchBelow 100° C. within 2 min

Hydrogenation (HYD) reaction conditions for benzene (model feed) areshown in the Table D below, and also detailed in the Experiment section:

TABLE D Reactor 1 L batch autoclave Catalyst precursor Organo metalliccompounds of nickel, molybdenum and tungsten Sulfiding agent DMDS, CS₂Feed benzene Solvent hexadecane Atomsphere H₂ Stir rate 750 rpm ReactionTemperature ramping RT → 382° C. in 2 hr conditions Pressure 1800 psigTemperature 382° C. (720° F.) Residence time 0.5 hr quench Below 100° C.within 2 min

HDS and HDN reaction conditions for Heavy Coker Gas Oil (properties inTable A) are listed below in Table E, and also detailed in theExperiment section:

TABLE E Reactor 1 L batch autoclave Catalyst precursor Organo metalliccompounds of nickel, molybdenum and tungsten Sulfiding agent DMDS, CS₂feed Heavy Coker Gas Oil solvent Hexadecane Atomsphere H₂ Stir rate 750rpm Sulfiding Temperature RT → 250° C. (40 min) → 250° C. (2.5hr) →Conditions ramping 343° C. (70 min) → 343° C. (2hr) Pressure 1800 psigQuench Below 100° C. within 2 min Reaction Temperature RT → 382° C. in 2hr conditions ramping Pressure 1800 psig Temperature 382° C. (720° F.)Residence time 0.5 hr Quench Below 100° C. within 2 minHDS and HDN reaction conditions for Heavy Vacuum Gas Oil (properties inTable B) are shown in the Table F below, and also detailed in theExperiment section:

TABLE F Reactor 1 L batch autoclave Catalyst precursor Hydroxidecatalyst precursor Sulfiding agent DMDS in straight run diesel with 2.5wt % sulfur Feed Heavy Vacuum Gas Oil Atomsphere H₂ SulfidingTemperature 400-500° F. for low temperature Conditions sulfidingfollowed by 600-700° F. for high temperature sulfiding Pressure 0-2700psig Reaction Temperature 700° F. conditions Pressure 2300 psig LHSV 2hr⁻¹ H₂ to feed ratio 5000 scf/bbl, once through H₂

Mixed metal sulfide (“MMS”) catalyst refers to a catalyst containingtransition metal sulfides of molybdenum, tungsten, and nickel in oneembodiment, and of nickel and molybdenum or nickel and tungsten in asecond embodiment and molybdenum and tungsten in yet another embodiment.

The size of crystalline domain L is determined by the Scherrer equationof L=kλ/(Δ(2θ)×cos θ); wherein λ is the wavelength of incident beam,when Cu kα1 is used, λ=1.5406 Å; k=0.89; Δ(2θ) is the FWHM (full widthat half maximum); and θ is an angular position of reflection peakmeasured in degrees.

“Hydroconversion” or “hydroprocessing” means any process that is carriedout in the presence of hydrogen, including, but not limited to,methanation, water gas shift reactions, hydrogenation, hydrotreating,hydrodesulphurization, hydrodenitrogenation, hydrodeoxygenation,hydrodecarboxylation, hydrodecarbonylation, hydrodemetallation,hydrodearomatization, hydroisomerization, hydrodewaxing andhydrocracking including selective hydrocracking Depending on the type ofhydroprocessing and the reaction conditions, the products ofhydroprocessing can show improved viscosities, viscosity indices,saturates content, density, low temperature properties, volatilities anddepolarization, etc. The reactions include one or more of: molecularweight reduction by catalytic or thermal cracking; heteroatom or metalremoval; asphaltene or carbon residue reduction; olefin or aromaticsaturation (ASAT); and skeletal or double bond isomerization.

Hydrogenolysis (“HYL”) refers to a reaction whereby a carbon-carbon orcarbon-heteroatom single bond is cleaved or undergoes “lysis” byhydrogen. The heteroatom is generally oxygen, sulfur, nitrogen, or aheavy metal. Catalytic hydrogenolysis commonly occurs inhydrodeoxygenation (HDO) to remove oxygen and hydrodesulfurization (HDS)to remove sulfur as the heteroatoms in oil feedstock. An example of HDOis shown below, wherein at least a portion of oxygen removal from phenoloccurs via the direct cleavage of the C(sp²⁾-O bond to form benzene.

An example of HDS is shown below, wherein at least a portion of sulfurremoval from dibenzylthiophene occurs via the direct cleavage of theC(sp²⁾-S bond (“HYL” reaction indicated by k_(sp)) to form biphenyl.

Hydrogenation (“HYD”), or treating with hydrogen, refers to a chemicalreaction between hydrogen and another compound, generally constitutingthe addition of hydrogen atoms to a molecule. Hydrogenation generallyoccurs in the hydrodenitrogenation (HDN) to remove nitrogen. An exampleof HDN is as illustrated below, wherein nitrogen removal from quinolinestarts from either partially hydrogenating, or fully hydrogenating thearomatic rings of the molecule before C—N bond breakage occur viahydrogenolysis followed by de-amination through Hofmann elimination:

Refineries increasingly have to deal with heavier feedstocks, such asrefractory feeds containing condensed aromatic sulfur compounds of alkyldibenzylthiophene type. With the ULSD requirements of 10-15 wppm, italso means that refineries have to desulfurize these sulfur compoundsdown to below the specified levels. The complex sulfur molecules behavesimilarly to the aromatic nitrogen species, requiring to be hydrogenated(HYD) first before the C—S bond cleavage (HYL).

Traditionally, catalysts for hydroprocessing of refractory feedstockscomprise molybdenum sulfide and tungsten sulfide catalysts with some ofthe Mo (or W) cations substituted by promoter metal Co or Ni. Theresultant cobalt molybdenum sulfide system is recognized for enhancedHYL activities as it is generally believed that the presence of cobaltfacilitates the C—S bond cleavage. On the other hand, nickel tungstensulfide and nickel molybdenum sulfide systems are recognized forenhanced HYD activities.

In one embodiment, the invention relates to self-supported MMS catalystshaving optimized hydrogenation (HYD) and hydrogenolysis (HYL)activities, and thus outstanding HDN and HDS performance. The inventionalso relates to methods of preparation of self-supported catalysts withbalanced hydrogenation (HYD) and hydrogenolysis (HYL) activities for thehydroprocessing of refractory feeds. In one embodiment, theself-supported MMS catalysts contain at least two metals from Group VIB,e.g., Mo and W, and at least a metal from Group VIII, such as Ni, andmultiphase combinations thereof.

Self-supported Catalyst Having Optimized HDS/HDN Activities: It wasdiscovered that a MMS catalysts containing nickel, tungsten, andmolybdenum sulfides within a range of optimum metal ratios exhibit aunique combination of both the enhanced HYL activity of the mixedmolybdenum tungsten sulfide and the enhanced HYD activity of the mixednickel tungsten or nickel molybdenum sulfides, and consequently enhancedcombinations of HDS and HDN activities compared to MMS catalysts ofbinary metal sulfide compositions. It was also discovered that a MMScatalysts containing tungsten and molybdenum sulfides within a widerange of compositions exhibit synergy between the components asmanifested in improved HYL activity and therefore enhanced HDS activitywhen compared to molybdenum sulfide catalysts. It was further discoveredthat in a mixed nickel tungsten sulfide catalyst systems having thenickel-to-tungsten ratio within an optimum range, there is synergybetween the components such as that an active nickel phase enhances theHYD activity of the catalyst and therefore HDN activity, as compared toeither active nickel or tungsten sulfide catalysts. A similar effect wasobserved for a mixed nickel molybdenum sulfide catalyst system.

With respect to the BET surface area and pore volume (PV)characteristics, the self-supported MMS catalyst containing molybdenum,tungsten, and nickel sulfides in the optimum compositional range in oneembodiment is characterized as having a BET surface area of at least 20m²/g, and a pore volume of at least 0.05 cm³/g. The BET surface is atleast 30 m²/g in a second embodiment, and at least 40 m²/g in a thirdembodiment. The MMS catalyst is further characterized as having minimalshrinkage, with a surface area of at least 20% of the original value(i.e., a surface are reduction of less than 80%) after being exposed toa Heavy Coker Gas Oil of at least 0.5 hrs in a hydrotreating process.The original value refers to the surface area of the freshly preparedcatalyst prior to the exposure. Examination of the XPS data for aself-supported MMS catalysts containing molybdenum, tungsten, and nickelwithin an optimum composition range shows a Ni surface concentration toNi bulk concentration ratio of at least 0.4 mol/mol; a W surfaceconcentration to W bulk concentration ratio of at least 0.3 mol/mol inone embodiment; a Ni surface/Ni bulk concentration ratio of at least 0.5mol/mol; and a W surface/W bulk concentration ratio of at least 0.4mol/mol in another embodiment.

In one embodiment, the self-supported mixed metal sulfide catalystsexhibiting a combination of optimum HYL and HYD performance inhydrotreating are characterized by having an optimized Ni:Mo:Wcomposition with a range of Ni/(Ni+W+Mo) ratios of0.25≦Ni/(Ni+Mo+W)≦0.8, a range of Mo/(Ni+Mo+W) molar ratios of 0.0Mo/(Ni+Mo+W)≦13.25, and a range of W/(Ni+Mo+W) molar ratios of0.12≦W/(Ni+Mo+W)≦0.75

In another embodiment, a self-supported catalyst exhibits optimumperformance when the relative molar amounts of nickel, molybdenum andtungsten are within a compositional range defined by five points ABCDEin the ternary phase diagram of FIG. 1, showing the element contents ofnickel, molybdenum and tungsten in terms of their molar fractions. Thefive points ABCDE are defined by A (Ni=0.80, Mo=0.00, W=0.20), B(Ni=0.25, Mo=0.00, W=0.75), C (Ni=0.25, Mo=0.25, W=0.50), D (Ni=0.63,Mo=0.25, W=0.12), E (Ni=0.80, Mo=0.08, W=0.12).

In one embodiment, the molar ratio of metal components Ni:Mo:W is in arange of: 0.33≦Ni/(Mo+W)≦2.57, a range of Mo/(Ni+W) molar ratios of0.00≦Mo/(Ni+W)≦0.33, and a range of W/(Ni+Mo) molar ratios of0.18≦W/(Ni+Mo)≦3.00. In yet another embodiment, the molar ratios ofmetal components Ni:Mo:W in a region is defined by six points ABCDEF ofa ternary phase diagram, and wherein the six points ABCDEF are definedas: A (Ni=0.67,Mo=0.00,W=0.33), B (Ni=0.67, Mo=0.10, W=0.23), C(Ni=0.60, Mo=0.15, W=0.25), D (Ni=0.52, Mo=0.15, W=0.33), E (Ni=0.52,Mo=0.06, W=0.42), F (Ni=0.58, Mo=0.0, W=0.42). In another embodiment,the molar ratio of metal components Ni:Mo:W in a range of:1.08<=Ni/(Mo+W)<=2.03; 0<=Mo/(Ni+W)<=0.18; and 0.33<=W/(Mo+Ni))<=0.72.

In yet another embodiment, the molar ratios of metal components Ni:Mo:Win a region is defined by four points ABCD of a ternary phase diagram,and wherein the four points ABCD are defined as:A(Ni=0.67,Mo=0.00,W=0.33), B(Ni=0.58, Mo=0.0, W=0.42), C(Ni=0.52,Mo=0.15, W=0.33), D(Ni=0.60, Mo=0.15, W=0.25).

In one embodiment, a bi-metallic nickel tungsten sulfide self-supportedcatalyst exhibits optimum HYD and HDN performance when the relativemolar amounts of nickel, and tungsten are in an optimum range defined byE (Ni=0.25, W=0.75) and F (Ni=0.8, W=0.2) in the ternary phase diagramof FIG. 2, for a Ni:W molar ratio ranges from 1:3 to 4:1, on atransition metal basis). In yet another embodiment, the bi-metalliccatalyst further comprises a metal promoter selected from Mo, Nb, Ti,and mixtures thereof, wherein the metal promoter is present in an amountof less 1% (mole).

In another embodiment, a bi-metallic molybdenum tungsten sulfideself-supported catalyst exhibits improved HYL and HDS performancecomparing to molybdenum sulfide alone or tungsten sulfide alone when therelative molar amounts of nickel, and tungsten are in the optimum rangedefined by G (Mo=0.001, W=0.999) and H (Mo=0.999, W=0.001) in theternary phase diagram of FIG. 3 (with at least 0.1 mol % of Mo and atleast 0.1 mol % of W, on a transition metal basis).

It is observed that the MMS catalyst containing molybdenum, tungsten,and nickel within an optimum composition range has a variation of HDSreaction rate constant and an HDN reaction rate constant (afternormalized to surface area and Ni surface concentration) within 20%,independent of the starting metal precursors, and independent of whetherprepared from inorganic metal salts or organo-metallic compounds asstarting reagents.

In one embodiment, the self-supported catalysts are prepared fromsources of nickel, molybdenum and tungsten in their elemental, compound,or ionic form (“metal precursors”). Examples of molybdenum precursorsinclude but are not limited to alkali metal molybdates (e.g. alkalimetal heptamolybdates, alkali metal orthomolybdates, alkali metalisomolybdates), ammonium metallates of molybdenum (e.g., ammoniummolybdate and also iso-, peroxo-, di-, tri-, tetra-, hepta-, octa-, ortetradecamolybdate), other inorganic molybdenum compounds (e.g.molybdenum sulphate, phosphate, silicate, borate), organic molybdenumcompounds (e.g., molybdenum naphthenate, pentacyclodienyl molybdate,cyclopentadienyl Mo tricarbonyl dimer,), alkali metal tungstates (e.g.alkali metal heptatungstates, alkali metal orthotungstates, alkali metaliso tungstates), ammonium metallates of tungsten (e.g., ammoniumtungstate and also iso-, peroxo-, di-, tri-, tetra-, hepta-, octa-, ortetradeca tungstate), other inorganic tungsten compounds (e.g. tungstensulphate, phosphate, silicate, borate), organic tungsten compounds(e.g., tungsten naphthenate, pentacyclodienyl tungsten dihydride), otherinorganic nickel, molybdenum or tungsten single metal or compounds (e.g.ammonium salts of phosphomolybdic acids, phosphomolybdic acid,molybdenum oxide, tungsten oxide, nickel carbonate, nickel hydroxide,nickel phosphate, nickel phosphite, nickel formate, nickel fumarate,nickel molybdate, nickel tungstate, nickel oxide, nickel alloys such asnickel-molybdenum alloys, Rancy nickle, etc.), ionic salts (e.g., Mo—Pheteropolyanion compounds, Mo—Si heteropolyanion compounds, W—Pheteropolyanion compounds, W—Si heteropolyanion compounds and Ni—Mo—Wheteropolyanion compounds), and organo metallic compounds (e.g.,cyclopentadienyl nickel, and nickel naphthenate). In one embodiment, themetal precursors are inorganic metal sulfides of nickel, molybdenum,tungsten and their combinations, e.g., Ni₃S₂, Ni₉S₈, Ni₂S, NiS, MoS₃,MoS₂, WS₃, WS₂, MoWS_(x), NiMoS_(x), NiWS_(x), NiMoWS_(x). In anotherembodiment, the metal precursors are single metal or sulfur-containingcompounds, which can be inorganic or organic. Examples include but arenot limited to, e.g., ammonia tetrathio molybdate, ammonia tetrathiotungstate, and Molyvan™ A, a commercially available materia fromR.T.Vanderbilt Co., Inc.

In one embodiment, the MMS catalysts are prepared by sulfiding an oxideor hydroxide catalyst precursor containing nickel, molybdenum andtungsten with a composition inside the optimum range. The catalystprecursor is optionally prepared in the presence of a ligand “L”(“ligating agent,” “chelating agent” or “complexing agent” or chelator,or chelant), referring to a compound that has one or more pairs ofelectrons available for the formation of coordinate bonds forming alarger complex. Examples of ligands include but are not limited to NH₃,alkyl and aryl amines, carboxylates, carboxylic acids, aldehydres,ketones, the enolayte forms of aldehydes, the enolate forms of ketones,and hemiacetals; organic acid addition salts, and mixtures thereof.

In one embodiment, molybdenum and tungsten metal precusors are firstmixed with at least one ligand, with the resulting solution mixed withthe nickel metal precursor, under reacting conditions to form a slurry(a gel or suspended precipitate). It should be understood that thecatalyst precursor preparation is not limited to aqueous media, and theaddition of the metal precusors/ligand can be in any order, and canmixed separately or together with the optional ligand if present. In oneembodiment, the reaction occurs at a temperature between 25-350° C. andat a pressure between 0 to 3000 psig. The pH of the reaction mixture canbe changed to increase or decrease the rate of precipitation (cogel orcogellation).

After the co-precipitation step, the catalyst precursor is isolated orrecovered in a liquid removal step using known separation processes suchas filtering, decanting or centrifuging, then dried to further removewater. Binders (or diluents), pore forming agents, and other additivesknown in the art can be incorporated into the catalyst precursor beforebeing optionally shaped by processes known in the art, e.g., extrusion,pelleting, or pilling. In one embodiment, the catalyst precursor isthermally treated or dried at a temperature between 50° C. to 200° C.for a hydroxide catalyst precursor. In another embodiment, the precursoris calcined at a temperature of at least 300° C. and preferably at least325° C. after shaping. In one embodiment, the catalyst precursor isprepared from nickel, molybdenum, and tungsten metal precursors in theform of organo-metallic compounds of nickel, molybdenum, and tungsten,as starting materials, in amounts sufficient to form a catalystprecursor containing nickel, molybdenum, and tungsten in the optimizedcompositional range. In another embodiment, the catalyst precursor isprepared by reacting at least a metal precursor, e.g., Ni, Mo, or W,with a single metal sulfide or a sulfide, e.g., nickel tungstensulfides, nickel molybdenum sulfides, molybdenum tungsten sulfides etc.,or a sulfur-containing metal compound such as Molyvan A, forming acatalyst precursor containing nickel, molybdenum, and tungsten in theoptimized compositional range.

In one embodiment, the starting materials are first mixed in oxygen freesolvent before the addition of sulfiding agents. Sulfiding agents suchas dimethyl disulfide or carbon disulfide are added to the catalystprecursor to form the self-supported catalyst. Sulfiding reaction toform mixed metal sulfides in one embodiment occurs at a temperaturebetween 200-450° C. and at a hydrogen pressure between 0-3000 psig.

The catalyst precursor can be sulfided under conditions sufficient to atleast partially convert, and generally to substantially convert thecomponents of the catalyst precursor into a metal sulfide. Suitablesulfiding conditions include heating the precursor in an atmospherecontaining a sulfiding agent, e.g., H₂S, dimethyl disulfide, inorganicor organic polysulfides, etc., at a temperature ranging from 25° C. to500° C., from 10 minutes to 15 days, and under a H₂-containing gaspressure. The sulfiding with a gaseous sulfiding agent such as H₂S canbe done ex-situ or in-situ, e.g., in the unit in which the catalyst willeventually be used for hydrotreating the hydrocarbon feeds.

Further details regarding methods for making the oxide or hydroxidecatalyst precursor containing nickel, molybdenum and tungsten in theoptimum compositional range, and sulfided catalyst formed from the oxideor hydroxide catalyst precursor thereof are described in a number ofpatent applications and patents, including U.S. Pat. No. 8,080,492, U.S.Pat. No. 8,058,203, U.S. Pat. No. 7,964,526, U.S. Pat. No. 7,931,799,U.S. Pat. No. 7,964,525, U.S. Pat. No. 7,544,285, U.S. Pat. No.7,615,196, U.S. Pat. No. 6,635,599, U.S. Pat. No. 6,635,599, U.S. Pat.No. 6,652,738, U.S. Pat. No. 7,229,548, U.S. Pat. No. 7,288,182, U.S.Pat. No. 6,566,296, U.S. Pat. No. 6,860,987, U.S. Pat. No. 6,156,695,U.S. Pat. No. 6,162,350, U.S. Pat. No. 6,299,760, U.S. Pat. No.6,620,313, U.S. Pat. No. 6,758,963, U.S. Pat. No. 6,783,663, U.S. Pat.No. 7,232,515, U.S. Pat. No. 7,179,366, U.S. Pat. No. 6,274,530; USPatent Publication Nos. US10110190557A1, US20090112011A1,US20090112010A1, US20090111686A1, US20090111685A1, US20090111683A1,US20090111682A1, US20090107889A1, US20090107886A1, US20090107883A1,US2007090024, the relevant disclosures with respect to the catalystprecursor and mixed metal sulfide catalyst composition are includedherein by reference.

In one embodiment of a self-supported MMS catalyst containingmolybdenum, tungsten, and nickel in an optimum compositional range ischaracterized as being multiphased, wherein the structure of thecatalyst comprises five phases: a molybdenum sulfide phase, a tungstensulfide phase, molybdenum tungsten sulfide phase, an active nickelphase, and a nickel sulfide phase. The molybdenum, tungsten andmolybdenum tungsten sulfide phases comprise at least a layer, with thelayer comprising at least one of: a) molybdenum sulfide and tungstensulfide; b) tungsten isomorphously substituted into molybdenum sulfideeither as individual atoms or as tungsten sulfide domains; c) molybdenumisomorphously substituted into tungsten sulfide either as individualatoms or as molybdenum sulfide domains; and d) mixtures of theaforementioned layers.

In one embodiment, the number of layers ranges from 1-6. In oneembodiment, the number of layers ranges from 1-6. In another embodimentas illustrated in FIG. 17, the molybdenum tungsten sulfide phase ispresent as tungsten atomically substituted into molybdenum sulfidelayers (or vise versa), forming an intralayer atomic mixture. In anotherembodiment, the molybdenum tungsten sulfide phase is present as aninter-layer mixture of tungsten sulfide and molybdenum sulfide. In yetanother embodiment, it is present as a mixture of individual domains oftungsten sulfide and molybdenum sulfide. The molybdenum tungsten sulfidephase can be observed via TEM or XRD.

The active nickel phase can be observed via TEM. The active nickel phasecomprises: a) at least one of atomic nickel (e.g., in metallic state)and reduced nickel (e.g., nickel in an oxidation state lower than 2)substituted into the edge of molybdenum tungsten sulfide phase (for atri-metallic catalyst) or tungsten sulfide phase (for a bi-metallic Ni:Wcatalyst), and b) NiS_(x) nanoparticles (0≦x≦1) dispersed onto themolybdenum tungsten sulfide phase or decorating the edge of themolybdenum tungsten sulfide phase (for a tri-metallic catalyst) ortungsten sulfide phase (for a bi-metallic Ni:W catalyst).

The nickel sulfide phase comprises slabs of both Ni₉S₈ and Ni₃S₂crystals. The large, nickel sulfide slabs serve as support for thegrowth of molybdenum tungsten sulfide (for a tri-metallic catalyst) ortungsten sulfide phase (for a bi-metallic Ni:W catalyst), and stabilizethe dispersion of active nickel on the surface of molybdenum tungstensulfide (for a tri-metallic catalyst) or tungsten sulfide (for abi-metallic Ni:W catalyst).

SEM examination shows that the nickel sulfide phase comprises aplurality of slabs. XRD and TEM examination show that the nickel sulfidephase comprises at least one of Ni₉S₈ and Ni₃S₂. The large nickelsulfide crystalline slabs serve as support for the molybdenum tungstensulfide and stabilize the dispersion of active nickel on the surface ofmolybdenum tungsten sulfide (for a tri-metallic catalyst) or tungstensulfide (for a bi-metallic Ni:W catalyst).

Not wishing to be bound by any theory, it is believed that themolybdenum tungsten sulfide phase acts as a support for the activenickel phase. In turn, the nickel sulfide phase stabilizes thedispersion of the molybdenum tungsten sulfide phase. Molybdenum tungstensulfide phase envelops the nickel sulfide slabs, so that the molybdenumtungsten sulfide layers exhibit a curved shape. Furthermore, themolybdenum tungsten sulfide phase develops defects in its lamellarcrystalline structure on basal planes, creating special sites associatedwith increased HYL and/or HYD activity. The specific interactions ofmultiple phases result in a catalyst with enhanced HYD and HYLactivities and with outstanding HDN and HDS performance. It should alsobe noted that different catalyst preparation routes, e.g. starting fromdecomposition of catalyst precursors in the form of organo-metalliccompounds or co-precipitation of mixed metal oxohydroxide starting fromoxygen-containing metal compounds may result in catalysts with a similarmetal composition but different catalytic activities.

In one embodiment, examination of the morphology of a self-supportedcatalyst tuned for optimum HYL and HYD activities with 50 mol-% Ni, 25mol-% Mo and 25 mol-% W exhibits an XRD pattern containing peaks thatare characteristic of Ni₃S₂ crystalline phase as illustrated in FIG. 4.As FIG. 4 illustrates, the XRD pattern exhibits reflection peaksindicative of the presence of molybdenum tungsten sulfide (according tointernational crystallographic database or ICDD), e.g., at 14.4°, 32.7°,39.5°, 49.8° and 58.3° 2θ degree. In another embodiment as illustratedin FIG. 5, the XRD pattern exhibits reflection peaks corresponding tothe presence of Ni₃S₂ phase (according to ICDD), e.g., at 21.8°, 31.1°,37.8°, 44.3°, 49.7°, 50.1° and 55.2° 2θ degree.

In one embodiment, TEM images of the nickel sulfide phase of aself-supported mixed metal sulfide catalyst within the optimumcompositional range exhibit lattice fringes with 4.60±0.5 Å spacing,corresponding to the [002] plane of Ni₉S₈ and with 2.87 Å±0.5 Å spacing,corresponding to [110] plane of Ni₃S₂. These observations indicate thatthe nickel sulfide phases are crystalline. They further suggest that thenickel sulfide phase serves as nucleation site (support) for the growthof the molybdenum tungsten sulfide phase which stabilizes the activenickel dispersion. In another embodiment, TEM images suggest that activenickel in the form of NiS_(x) nano-particles appear to be located on themolybdenum tungsten sulfide slabs or more likely decorating the edge ofmolybdenum tungsten sulfide slabs. FIG. 7 is an illustrative TEM imageshowing the presence of nickel sulfide as a combination of largecrystals of Ni₉S₈ and Ni₃S₂. FIG. 8 is another illustrative TEM image,showing the presence of active nickel in the form of nano-particles ofnickel sulfide.

XRD/TEM images illustrate how nickel sulfide supports molybdenumtungsten sulfide. Active nickel is in the form of NiS_(x) nanoparticlesdispersed onto the molybdenum tungsten sulfide and in the form oflow-oxidation-state nickel substituted into molybdenum tungsten sulfide.

FIG. 9 is another TEM image showing the presence of molybdenum tungstensulfide particles, wherein the molybdenum tungsten sulfide particlecurvature appears to follow the curvature of the nickel sulfide particlesurface. The curvature in the molybdenum tungsten sulfide phaseminimizes the height to which individual molybdenum tungsten particlescan stack, and it decreases the size of the individual molybdenumtungsten sulfide particles. A curvature and a reduction of size anddegree of stacking in molybdenum/tungsten sulfide particles leads to ahigher density of sites active for HYD and HYL. In one embodiment,molybdenum/tungsten particles exhibit a stacking degree of 1-6 (layers)and a layer dimension of 30-50 Å, estimated by the Scherrer equationusing the 2-4° FWHM (full width at half max) measured at 14° and 59°2θdegree, respectively. The inter-planar distance for the [002] plane is6.1 Å.

FIG. 16 is a pictorial representation of a TEM image showing that at theoptimum compositional range, the morphology mixed metal sulfides consistof large (about 10-20 nm in one embodiment) nickel sulfide slabs (Ni2S3or Ni9S8), with molybdenum tungsten sulfide layers enveloping thesenickel sulfide slabs. In the optimum compositional range, the molybdenumtungsten sulfide layers are arranged in stacks of about 1-4 layers withthe majority of the layers being undulating. Active nickel sulfide(NiSx) droplets of varying size (1-20 nm) reside at the edges of themolybdenum tungsten sulfide layers.

Hydrotreating Applications: The self-supported MMS catalysts containingmolybdenum sulfide and tungsten sulfide in an amount of at least 0.1mole % of Mo and 0.1 mole % of W have an HDS reaction rate constant ofat least 10% higher in one embodiment, at least 15% higher in anotherembodiment, than a self-supported catalyst containing molybdenum sulfidealone, or a catalyst containing tungsten sulfide alone, when compared onthe same metal weight basis in hydrotreating of a Heavy Coker Gas Oil asa feedstock at identical process conditions as indicated in Table E. Inanother embodiment, a molybdenum tungsten sulfide MMS catalyst exhibitsan HYL reaction rate constant of at least 10% above the HYL reactionrate constant of a self-supported catalyst containing molybdenum sulfidealone, or a catalyst containing tungsten sulfide alone in hydrotreatinga diphenylether, on the same metal molar basis at the process conditionsas indicated in Table C.

The self-supported MMS catalysts containing nickel and tungsten sulfideswithin an optimum composition range have a high HYD activity and therebyoutstanding HDN activities. Assuming first order kinetics, in oneembodiment, the catalyst is characterized as having a HDN reaction rateconstant of at least 4 hr⁻¹ on catalyst weight hourly space velocitybasis in hydrotreating a Heavy Vacuum Gas Oil (VGO) at the steady stateprocess conditions as indicated in Table F. In another embodiment, theHDN reaction constant is at least 4.5 hr⁻¹ on catalyst weight hourlyspace velocity basis. In another embodiment, the catalyst ischaracterized as having a HDN reaction rate constant of at least 100 gfeed·hr⁻¹·g catalyst⁻¹ on hydrotreating a Heavy Coker Gas Oil under theprocess conditions indicated in Table E. In another embodiment, thecatalyst is characterized as having a HDN reaction rate constant of atleast 110 g feed. hr⁻¹·g catalyst⁻¹. A nickel tungsten sulfide MMScatalyst exhibits an HYD reaction rate constant of at least 10% in oneembodiment, and at least 15% in another embodiment, above the HYDreaction rate constant of a self-supported catalyst containing tungstensulfide alone, or a catalyst containing nickel sulfide alone inhydrotreating benzene on the same metal molar basis at the processconditions as indicated in Table D.

The self-supported MMS catalysts containing molybdenum, tungsten, andnickel sulfides within an optimum range have a uniquely combined highHYL activity of MMS catalysts containing molybdenum and tungstensulfides, and high HYD activity of catalysts containing nickel andmolybdenum sulfides or catalysts containing nickel and tungstensulfides, and thereby outstanding HDN and HDS activities. In oneembodiment, assuming the first order kinetics, the catalyst ischaracterized as having a HDN reaction rate constant of at least 4 hr⁻¹on catalyst weight hourly space velocity basis, and a HDS reaction rateconstant of at least 5 hr⁻¹ on catalyst weight hourly space velocitybasis in hydrotreating a Heavy VGO at steady-state process conditions asindicated in Table F. In another embodiment, the HDN reaction constantat steady state conditions is at least 4.5 hr⁻¹ on catalyst weighthourly space velocity basis, and the HDS reaction rate constant is atleast 6 hr⁻¹ on catalyst weight hourly space velocity basis. In anotherembodiment, the catalyst is characterized as having initial activity asexpressed by a HDN reaction rate constant of at least 100 g feed·hr⁻¹·gcatalyst⁻¹, and a HDS reaction rate constant of at least 550 gfeed·hr⁻¹·g catalyst⁻¹ on hydrotreating a Heavy Coker Gas Oil at theprocess conditions as indicated in Table E. In another embodiment, thecatalyst is characterized as having a HDN reaction rate constant of atleast 110 g feed·hr⁻¹·g catalyst⁻¹ and a HDS reaction rate constant ofat least 600 g feed·hr⁻¹·g catalyst⁻¹.

In one embodiment, the MMS catalyst containing molybdenum, tungsten, andnickel sulfides is characterized as having a HYD reaction rate constantand a HYL reaction rate constant of at least 10% higher than therespective rate constants of a catalyst containing nickel and molybdenumsulfides, or a catalyst containing nickel and tungsten sulfides, whencompared on the same metal molar basis, in hydrotreating of adiphenylether as a feedstock at similar process conditions as indicatedin Table C and Table D. In another embodiment, the HYD and HYL reactionrate constants are at least 15% higher.

The self-supported MMS catalysts having compositions within the optimumrange and exhibiting combined high HYL and HYD activities areparticularly suitable for hydrotreating refractory petroleum feeds suchas heavy coker gas oils, LC Fining products, atmospheric residues (AR),vacuum gas oils (VGO), and particularly those derived from syntheticcrudes. Refractory feeds are commonly characterized as exhibitingrelatively high specific gravity, low hydrogen-to-carbon ratios, andhigh carbon residue. They contain significant amounts of asphaltenes,organic sulfur, organic nitrogen and metals, which increasehydrotreating difficulty and often results in the phase separationduring aromatics hydrogenation. Such refractory feeds typically exhibitan initial boiling point in the range of 343° C. (650° F.) to 454° C.(850° F.), more particularly an initial boiling point above 371° C.(700° F.).

In one embodiment, the self-supported catalyst particularly suitable forthe removal of high-boiling point sulfur species, including sulfurspecies boiling above 650° F. (343° C.), is used in the production ofultra-low sulfur diesel (ULSD) hydrocracker products, as well as in theproduction of naphtha acceptable as reformer feed.

EXAMPLES

The following illustrative examples are intended to be non-limiting. Inthe examples, either a model feed or a commercial feed was used witheither organo metallic compounds or oxide/hydroxide precursors asstarting reagents in preparation of mixed metal sulfide catalystscatalytic reactions were carried out in order to examine the activity ofthe catalysts containing combinations of active nickel, molybdenum andtungsten phases, so as to quantify the optimum ranges in terms ofchemical compositions. The structure and composition of the MMS wasdetermined using analytical techniques such as inductively coupledplasma (ICP) atomic emission spectroscopy (ICP AES), X-Ray PhotoelectronSpectroscopy (XPS) and X-Ray Diffraction Analysis (XRD). Surface areawas determined by BET (BET from Brunauer, Emmett, Teller) method usingnitrogen adsorption isotherm measurements. Additional information onstructural details and chemical composition of the mixed metal sulfidematerials was obtained using Scanning Electron Microscopy (SEM) andtransmission electron microscopy (TEM).

Hydrogenolysis activity of catalysts was determined by measuring thereaction rate of cleavage of C(sp²)-O bond in diphenylether model feedas shown below. Reaction rate constant k1 is the rate constant ofhydrogenolysis reaction of C(sp²)-O-bond. There was no direct oxygenextrusion and partial hydrogenation detected.

Hydrogenation activity was determined using the reaction rate of benzenemodel feed into cyclohexane, as shown below. Reaction rate constant k4is the hydrogenation rate constant for the benzene to cyclohexanereaction:

HYL/HYD Activity Evaluation using Model Feeds: In the examples thatfollow, HYL/HYD activities were evaluated using model feeds. Thecatalysts were prepared starting from organo-metallic compounds. Aftercharging starting metal reagents, a sulfiding agent, model feedcompounds and hexadecane, as a diluent, were added to a 1-L batchautoclave. The autoclave was sealed after purging with H₂ for 10 min.The reaction mixture was stirred at 750 rpm. The reactor waspre-pressurized to 1000 psig in H₂ at RT, followed by ramping to areaction temperature of 382° C. (720° F.) in 2 hrs at a constant heatingrate. After 30 min of reaction at 382° C. and ˜1800 psig, the reactorwas quenched to below 100° C. in ˜2 min with cold water. The reactionmixture was recovered from the reactor and filtered through 0.8 μmfilter to collect a spent catalyst. After washing of the spent catalystwith sufficient amount of heptane, the catalyst was characterized usingtechniques including: ICP, XRD, XPS, BET, SEM and TEM.

The HYL reaction rate constant is defined as:

$k_{HYL} = {{\ln \left( \frac{1}{1 - {x\left( {{diphenylether}\mspace{14mu} {conversion}} \right)}} \right)} \times \frac{1}{{residence}\mspace{14mu} {time}} \times \frac{1}{{mole}\mspace{14mu} {of}\mspace{14mu} {total}\mspace{14mu} {catalyst}\mspace{14mu} {metal}}}$

The HYD reaction rate constant is defined as:

$k_{HYD} = {{\ln \left( \frac{1}{1 - {x\left( {{benzene}\mspace{14mu} {conversion}} \right)}} \right)} \times \frac{1}{{residence}\mspace{14mu} {time}} \times \frac{1}{{mole}\mspace{14mu} {of}\mspace{14mu} {total}\mspace{14mu} {catalyst}\mspace{14mu} {metal}}}$

HDS/HDN Activity Evaluation using Refinery Feeds: In a number ofexamples, HDS/HDN activities of catalysts were evaluated using refineryfeeds. The catalysts were prepared from either organo- metalliccompounds or hydroxide precursors. The refinery feeds were a Heavy CokerGas Oil and a Heavy Vacuum Gas Oil.

The tests with Heavy Coker Gas Oil as the reactor feed were performedaccording to the following procedure. Metal containing startingreagents, sulfiding agents and hexadecane solvent were loaded into a 1-Lbatch autoclave. The autoclave was sealed after purging with H₂ for 10min. The sulfiding reaction mixture was stirred at 750 rpm. The reactorwas pre-pressurized to 1000 psig with H₂. The reaction temperature wasramped to 250° C. (480° F.) in 40 min and then was kept constant for 2.5hrs, followed by a further temperature ramp to 343° C. (650° F.) in 70min. After 2 hr at 343° C. the reactor was quenched with cold water toRT. Catalyst activity evaluation was carried out by hydrotreating aHeavy Coker Gas Oil. 120 g of heavy coker gas oil were charged into theautoclave containing a freshly prepared sulfide catalyst. The autoclavewas sealed after purging with H₂ for 10 min. The reaction mixture wasstirred at 750 rpm. The reactor was pressurized to 1000 psig with H₂ atroom temperature (RT) followed by ramping to a reaction temperature of382° C. (720° F.) in 2 hrs at a constant heating rate. After 30 min ofreaction at 382° C. and 1800 psig, the reactor was quenched to below100° C. in ˜2 min with cold water. The reaction mixture was recoveredfrom the reactor and filtered through 0.8 μm filter to collect a spentcatalyst. After washing of the spent catalyst with sufficient amount ofheptane, the catalyst was characterized using ICP, XRD, XPS, BET, SEMand TEM.

The HDS reaction rate constant is defined as:

$k_{HDS} = {{\ln \left( \frac{1}{1 - {x({HDS})}} \right)} \times \frac{1}{{residence}\mspace{14mu} {time}} \times \frac{{gram}\mspace{14mu} {of}\mspace{14mu} {feed}}{{gram}\mspace{14mu} {of}\mspace{14mu} {catalyst}}}$

The conversion of HDS is between 30% and 67%.

The HDN reaction rate constant is defined as:

$k_{HDN} = {{\ln \left( \frac{1}{1 - {x({HDN})}} \right)} \times \frac{1}{{residence}\mspace{14mu} {time}} \times \frac{{gram}\mspace{14mu} {of}\mspace{14mu} {feed}}{{gram}\mspace{14mu} {of}\mspace{14mu} {catalyst}}}$

The conversion of HDN is between 8% and 27%.

In examples describing the use of a Heavy Vacuum Gas Oil feed, ahydroxide catalyst precursor was ground to 20-40 mesh and loaded into afixed bed reactor. Catalyst sulfiding was conducted following a liquidphase sulfiding procedure wherein a straight run diesel feed containing2.5 wt % DMDS was used as a sulfiding agent. Sulfiding of the catalystprecursor occurred in two steps: a 400-500° F. low temperature sulfidingstep followed by a 600-700° F. high temperature sulfiding. The reactionconditions for Heavy Vacuum Gas Oil hydrotreating were as follows:T=700° F., P=2300 psig, LHSV=2.0 hr⁻¹, once through hydrogen, H₂ to feedratio=5000 scf/bbl.

The HDS reaction rate constant is defined as:

$k_{HDS} = {{\ln \left( \frac{1}{1 - {x({HDS})}} \right)} \times \frac{{liquid}\mspace{14mu} {feed}\mspace{14mu} {rate}\mspace{14mu} \left( \frac{g}{hr} \right)}{{catalyst}\mspace{14mu} {weight}}}$

The conversion of HDS is greater than 95% for all tested catalysts.

The HDN reaction rate constant is defined as:

$k_{HDN} = {{\ln \left( \frac{1}{1 - {x({HDN})}} \right)} \times \frac{{liquid}\mspace{14mu} {feed}\mspace{14mu} {rate}\mspace{14mu} \left( \frac{g}{hr} \right)}{{catalyst}\mspace{14mu} {weight}}}$

The conversion of HDN is greater than 95% for all tested catalysts.

Example 1

Experiments were carried out according to previously describedprocedures for the HYL/HYD activity evaluation of single componentsulfide catalysts, e.g., nickel sulfide, molybdenum sulfide and tungstensulfide. For the HYL activity evaluation, 0.93 g Molyvan A as amolybdenum source, or 0.83 g cyclopentadienyl tungsten dihydride as atungsten source, or 2.57 g Ni naphthenate (6 wt % Ni in toluene) as anickel source, was charged into 1-L batch autoclave together withreaction feed of 23.81 g diphenylether and 100 g hexadecane. Nosulfiding agent was added to prepare a molybdenum sulfide catalyst.Carbon disulfide (CS₂) 0.4 g was added to sulfide tungsten into tungstensulfide. 0.25 g of dimethyl disulfide (DMDS) was added to sulfide nickelinto nickel sulfide. Spent catalyst samples were collected andcharacterized after reaction.

For the HYD activity evaluation, the experiments were repeated but with5.46 g benzene and 100 g hexadecane as the reaction feed.

Table 1 lists hydrogenolysis and hydrogenation activities of the singlemetal catalysts Ni₃S₂, MoS₂, WS₂. Both activities are considered to below.

TABLE 1 Catalyst Hydrogenolysis activity Hydrogenation activitycombination (hr⁻¹ mol⁻¹) × 10³ (hr⁻¹ mol⁻¹) × 10² MoS₂ 0.8 1.0 WS₂ 0.91.4 Ni₃S₂ 0.2 0.2

Example 2

Experiments were carried out according to previously describedprocedures for the HDS/HDN activity evaluation of single componentsulfide catalysts, e.g., nickel sulfide, molybdenum sulfide, tungstensulfide in the hydrotreatment of a Heavy Coker Gas Oil feed. 0.93 gMolyvan A as molybdenum catalyst precursor; or 0.83 g cyclopentadienyltungsten dihydride as tungsten catalyst precursor, or 2.57 g Ninaphthenate(6 wt % Ni in toluene) as nickel catalyst precursor, wascharged into 1-L batch autoclave together with a reaction feed of 120 gof Heavy Coker Gas Oil and 100 g hexadecane. No sulfiding agent wasadded to prepare the molybdenum sulfide catalyst. 0.4 g of carbondisulfide (CS₂) was added to sulfide tungsten to prepare tungstensulfide, 0.25 g of dimethyl disulfide (DMDS) was added to sulfide nickelto prepare nickel sulfide. Spent catalyst samples were collected andcharacterized after the reaction.

Table 2 lists the HDS and HDN activities of the single metal catalystsNi₃S₂, MoS₂, WS₂. Both activities are considered to be weak.

TABLE 2 Catalyst Hydrogenolysis activity Hydrogenation activitycombination (hr⁻¹ mol⁻¹) × 10³ (hr⁻¹ mol⁻¹) × 10² MoS₂ 0.8 1.0 WS₂ 0.91.4 Ni₃S₂ 0.2 0.2

Example 3

Experiments were carried out according to previously describedprocedures for HYL/HYD activity evaluations of molybdenum tungstensulfide catalysts. For the HYL activity evaluation, Molyvan A andcyclopentadienyl tungsten dihydride at different ratios were chargedinto a 1-L batch autoclave together with a reaction feed of 23.81 gdiphenylether, 100 g hexadecane and carbon disulfide (CS₂) sulfidingagent. The charge ratios were 0.62 g Molyvan A to 0.28 gcyclopentadienyl tungsten dihydride, and 0.31 g Molyvan A to 0.55 gcyclopentadienyl tungsten dihydride. These correspond to a Mo:W molarratio of 2:1 and 1:2 respectively. Spent catalyst samples were collectedand characterized after the reaction.

For the HYD activity evaluation, the experiments were repeated but with5.46 g of benzene, 100 g of hexadecane as the reaction feed.

Table 3 lists the hydrogenolysis and hydrogenation activities of themolybdenum tungsten sulfide catalysts. There is a synergy betweenmolybdenum sulfide and tungsten sulfide as demonstrated by the increasedHYL activity, whereas HYD activity remains relatively low.

TABLE 3 Catalyst CS₂ Hydrogenolysis Hydrogenation combination chargeactivity activity (Ni, Mo, W mol-%) (g) (hr⁻¹ mol⁻¹) × 10³ (hr⁻¹ mol⁻¹)× 10² 0, 67, 33 0.25 1.1 0.4 0, 33, 67 0.5 1.3 0.5

Example 4

Experiments were carried out according to previously describedprocedures for HDS/HDN activity evaluation of molybdenum tungstensulfide catalysts in the hydrotreatment of a Heavy Coker Gas Oilfeedstock. 0.31 g of Molyvan A and 0.55 g of cyclopentadienyl tungstendihydride were charged into a 1-L batch autoclave, together with areaction feed of 120 g of Heavy Coker Gas Oil, 100 g of hexadecane and0.5 g of carbon disulfide (CS₂) sulfiding agent. Spent catalyst sampleswere collected and characterized after the reaction.

Table 4 lists the HDS and HDN activities of the molybdenum tungstensulfide catalysts. There is a synergy between molybdenum sulfide andtungsten sulfide, as demonstrated by the increased HDS activity, whereasHDN activity remains relatively low.

TABLE 4 Catalyst HDS activity HDN activity combination (g feed hr⁻¹/g (gfeed hr⁻¹/g (Ni, Mo, W mol-%) catalyst) × 10² catalyst) × 10² 0, 33, 673.6 0.5

Example 5

Experiments were carried out according to previously describedprocedures for HYL/HYD activity evaluations. For the HYL activityevaluation of a nickel molybdenum sulfide catalyst, 0.31 g Molyvan A and1.71 g nickel naphthenate (6 wt % Ni in toluene) were charged into 1-Lbatch autoclave, together with a reaction feed of 23.81 g ofdiphenylether, 100 g of hexadecane and 0.17 g of dimethyl disulfide(DMDS) sulfiding agent. Spent catalyst samples were collected andcharacterized after the reaction.

For the HYD activity evaluation of the nickel molybdenum sulfidecatalyst, the above experiment was repeated but with 5.46 g of benzene,100 g of hexadecane as the reaction feed. Spent catalysts were collectedand characterized after the reaction.

For the HYL evaluation of a nickel tungsten sulfide catalyst acombination of 0.28 g of cyclopentadienyl tungsten dihydride and 1.71 gof nickel naphthenate (6 wt % Ni in toluene) was charged into a1-L batchautoclave together with reaction feed of 23.81 g of diphenylether, 100 gof hexadecane, and 0.17 g of dimethyl disulfide (DMDS) and 0.13 g ofcarbon disulfide (CS₂) sulfiding agents. Spent catalyst samples werecollected and characterized after reactions.

For the HYD activity evaluation of the nickel tungsten sulfide catalystcombination, the above experiment was repeated but with 5.46 g ofbenzene, 100 g of hexadecane as the reaction feed. Spent catalysts werecollected and characterized after reactions.

Table 5 shows the HYL and HYD activities of the nickel molybdenumsulfide and nickel tungsten sulfide catalysts. There is a synergybetween nickel sulfide and molybdenum sulfide or nickel sulfide andtungsten sulfide, in promoting both HYL and HYD activities, inparticular a strong HYD activity of the nickel tungsten sulfidecatalyst.

TABLE 5 Catalyst combination Hydrogenolysis activity Hydrogenationactivity (Ni, Mo, W mol-%) (hr⁻¹ mol⁻¹) × 10³ (hr⁻¹ mol⁻¹) × 10² 67, 33,0 1.0 1.2 67, 0, 33 1.4 2.30

Example 6

Experiments were carried out according to previously describedprocedures for HDS/HDN activity evaluation of a nickel molybdenumsulfide catalyst and a nickel tungsten sulfide catalyst in thehydrotreatment of a Heavy Coker Gas Oil feed. For nickel molybdenumsulfide catalyst, 0.31 g of Molyvan A and 1.71 g of nickel naphthenate(6 wt % Ni in toluene) were charged into a 1-L batch autoclave togetherwith a reaction feed of 120 g of Heavy Coker Gas Oil, 100 g ofhexadecane and 0.17 g of dimethyl disulfide (DMDS) sulfiding agent. Fornickel tungsten sulfide catalyst, 0.28 g of cyclopentadienyl tungstendihydride and 1.71 g of nickel naphthenate (6 wt % Ni in toluene) werecharged into a 1-L batch autoclave together with a reaction feed of 120g of Heavy Coker Gas Oil, 100 g of hexadecane and 0.17 g of dimethyldisulfide (DMDS) and 0.13 g of carbon disulfide (CS₂) sulfiding agents.Spent catalyst samples were collected and characterized after reactions.

Table 6 summarizes the HDS and HDN activity data for the nickelmolybdenum sulfide and nickel tungsten sulfide catalysts. There is asynergy between nickel sulfide and molybdenum sulfide and between nickelsulfide and tungsten sulfide in promoting both HDS and HDN activities,in particular a strong HDN activity of the nickel tungsten sulfidecatalyst.

TABLE 6 Catalyst HDS activity HDN activity combination (g feed hr⁻¹/g (gfeed hr⁻¹/g (Ni, Mo, W mol-%) catalyst) × 10² catalyst) × 10² 67, 33, 05.9 1.2 67, 0, 33 6.0 1.5

Example 7

Experiments were carried out according to previously describedprocedures for HYL/HYD activity evaluation of a MMS catalyst containingnickel, molybdenum and tungsten sulfide. For the HYL evaluation, 0.23 gof Molyvan A, 0.21 g of cyclopentadienyl tungsten dihydride, and 1.28 gof nickel naphthenate (6 wt % Ni in toluene) as starting materials toprepare a MMS catalyst with 50 mol-% Ni, 25 mol-% Mo and 25 mol-% W werecharged into a of 1-L batch autoclave together with a reaction feed of23.81 g diphenylether, 100 g of hexadecane, 0.13 g of dimethyl disulfide(DMDS) and 0.10 g carbon disulfide (CS₂) sulfiding agents. Spentcatalyst samples were collected and characterized after reactions.

For the HYD activity evaluation, the experiment was repeated but with areaction feed of 5.46 g of benzene and 100 g of hexadecane. Spentcatalysts were collected and characterized after reactions.

Table 7 lists hydrogenolysis and hydrogenation activity data for the MMScatalyst, showing very strong HYL and HYD activities.

TABLE 7 Catalyst combination Hydrogenolysis activity Hydrogenationactivity (Ni, Mo, W mol-%) (hr⁻¹ mol⁻¹) × 10³ (hr⁻¹ mol⁻¹) × 10² 50, 25,25 2.0 3.4

Example 8

Experiments were carried out according to previously describedprocedures for HDS/HDN activity evaluation of a MMS catalyst with 50mol-% Ni, 25 mol-% Mo and 25 mol-% W in the hydrotreatment of a HeavyCoker Gas Oil feeds. Table 8 lists the HDS and HDN activity data for theMMS catalyst, showing very strong HDS and HDN activities of the MMScatalyst at the selected ratio.

TABLE 8 Catalyst HDS activity HDN activity combination (g feed hr⁻¹/g (gfeed hr⁻¹/g (Ni, Mo, W mol-%) catalyst) × 10² catalyst) × 10² 50, 25, 256.2 1.3

Example 9

Experiments were carried out according to previously describedprocedures for HYL/HYD activity evaluation of different MMS catalysts ofdifferent transition metal compositions. In one experiment, 0.13 g ofMolyvan A, 0.26 g of cyclopentadienyl tungsten dihydride, 1.42 g ofnickel naphthenate (6 wt % Ni in toluene) were charged into a 1-L batchautoclave together with a reaction feed of 23.81 g of diphenylether forHYL evaluation or 5.46 g of benzene for HYD evaluation, 100 ghexadecane, 0.14 g of DMDS and 0.13 g of carbon disulfide (CS₂). Atarget catalyst composition of a MMS catalyst was 55 mol-% Ni, 14 mol-%Mo and 31 mol-% W.

Table 9 lists the HYL and HYD activity data for the MMS catalyst showingo that HYL and HYD activities can be optimized by changing the catalystcomposition.

TABLE 9 Catalyst combination Hydrogenolysis activity Hydrogenationactivity (Ni, Mo, W mol-%) (hr⁻¹ mol⁻¹) × 10³ (hr⁻¹ mol⁻¹) × 10² 55, 14,31 1.9 3.4

Example 10

Experiments were carried out according to previously describedprocedures for HDS/HDN activity evaluation of different MMS catalystswith different metal compositions in hydrotreatment of a Heavy Coker GasOil feed. The amounts of starting materials used in catalystspreparations and catalyst activity evaluation results are as shown inTables 10 and 11. The results indicate that HDS and HDN activities ofMMS catalysts correlate strongly with the catalyst composition and thereis arrange of optimum transition metal ratios where the catalystactivity is the highest. In the tables, Molyvan A is the Mo startingreagent; cyclopentadienyl tungsten dihydride is the W starting reagent;Ni naphthenate (6 wt % Ni in toluene) is the Ni starting reagent.

TABLE 10 Catalyst HDS × 10² (g cyclopentadienyl nickel combination feedhr⁻¹/g Molyvan A tungsten dihydride naphthenate DMDS CS₂ (Ni, Mo, Wmol-%) catalyst) weight (g) weight (g) weight (g) weight (g) weight (g)55, 14, 31 5.8 0.13 0.26 1.42 0.27 0.12 55, 15, 30 7.5 0.14 0.25 1.400.14 0.12 56, 15, 29 6.9 0.14 0.25 1.43 0.14 0.12 58, 11, 31 5.5 0.100.26 1.49 0.15 0.13 58, 14, 28 7.9 0.13 0.23 1.49 0.14 0.11 60, 13, 277.3 0.12 0.22 1.54 0.15 0.11

TABLE 11 HDN × 10² (g cyclopentadienyl nickel Catalyst feed hr⁻¹/gMolyvan A tungsten dihydride naphthenate DMDS CS₂ (Ni, Mo, W mol-%)catalyst) weight (g) weight (g) weight (g) weight (g) weight (g) 55, 14,31 1.3 0.13 0.26 1.42 0.14 0.12 55, 15, 30 1.1 0.14 0.25 1.40 0.14 0.1256, 15, 29 1.8 0.14 0.25 1.43 0.14 0.12 58, 11, 31 1.5 0.10 0.26 1.490.15 0.13 58, 14, 28 1.2 0.13 0.23 1.49 0.14 0.11 60, 13, 27 1.5 0.120.22 1.54 0.15 0.11

Example 11

Experiments were carried out according to previously describedprocedures for HYL/HYD activity evaluation of different MMS catalystswith different transition metal mol-percentages outside the optimalmetal range. The results of activity evaluations and amounts of startingmaterials used in catalyst preparations are as shown in Table 12 and 13.The results indicate that for catalysts compositions outside of theoptimum range the HYD and HYL activities are reduced.

TABLE 12 Catalyst cyclopentadienyl nickel combination HYL × 10³ MolyvanA tungsten dihydride naphthenate DMDS CS₂ (Ni, Mo, W mol-%) (hr⁻⁻¹mol⁻¹) weight (g) weight (g) weight (g) weight (g) weight (g) 20, 40, 401.1 0.38 0.33 0.51 0.05 0.16 33, 33, 34 1.0 0.31 0.28 0.86 0.09 0.13 55,31, 14 1.1 0.29 0.11 1.42 0.14 0.06

TABLE 13 Catalyst cyclopentadienyl nickel combination HYD × 10² MolyvanA tungsten dihydride naphthenate DMDS CS₂ (Ni, Mo, W mol-%) (hr⁻¹ mol⁻¹)weight (g) weight (g) weight (g) weight (g) weight (g) 20, 40, 40 1.60.38 0.33 0.51 0.05 0.16 33, 33, 34 1.6 0.31 0.28 0.86 0.09 0.13 55, 31,14 1.1 0.29 0.11 1.42 0.14 0.06

Example 12

Experiments were carried out according to previously describedprocedures for HDS/HDN activity evaluation of different MMS catalystswith different transition metal mol-percentages in hydrotreatment of aHeavy Coker Gas Oil feed. The activity test results and amounts ofstarting materials used in catalysts preparations are as shown inTable14 and 15. The results indicate that for catalysts compositionsoutside of the optimum range, the HYD and HYL activities are reduced.

TABLE 14 Catalyst HDS × 10² (g cyclopentadienyl nickel combination feedhr⁻¹/g Molyvan A tungsten dihydride naphthenate DMDS CS₂ (Ni, Mo, Wmol-%) catalyst) weight (g) weight (g) weight (g) weight (g) weight (g)9:45.5:45.5 3.9 0.42 0.38 0.23 0.04 0.18 10:10:80 4.0 0.09 0.66 0.260.05 0.32 20:40:40 3.5 0.37 0.33 0.51 0.10 0.16 20:10:70 4.8 0.09 0.580.51 0.10 0.28 33:33:34 5.0 0.31 0.28 0.86 0.16 0.13

TABLE 15 Catalyst HDN × 10² (g cyclopentadienyl nickel combination feedhr⁻¹/g Molyvan A tungsten dihydride naphthenate DMDS CS₂ (Ni, Mo, Wmol-%) catalyst) weight (g) weight (g) weight (g) weight (g) weight (g)9:45.5:45.5 0.8 0.42 0.38 0.23 0.04 0.18 10:10:80 1.0 0.09 0.66 0.260.05 0.32 20:10:70 1.0 0.09 0.58 0.51 0.10 0.28 20:40:40 0.9 0.37 0.330.51 0.10 0.16 27:59:15 1.0 0.55 0.12 0.69 0.13 0.06 33:33:34 1.0 0.310.28 0.86 0.16 0.13

Example 13

In this experiment a MMS catalyst was prepared using a hydroxidecatalyst precursor containing 55 mol-% Ni, 14 mol-% Mo and 31 mol-% W.To prepare the hydroxide catalyst precursor, Ni(NO₃)₂.6H₂O,(NH₄)₆(MO₇O₂₄).4H₂O and (NH₄)₆H₂W₁₂O₄₀ were dissolved into water andco-precipitated by adding NH₄OH according to the procedure known in theart, e.g., Encyclopedia of Catalysis, for the co-precipitation reactionsof metal precursors.

0.353 g (on dry basis) of the catalyst precursor was charged into a 1-Lbatch autoclave together with 100 g of hexadecane and 0.25 g of carbondisulfide (CS₂) sulfiding agent. During catalyst sulfiding, the reactorwas sealed after purging in H₂ for 10 min. The reaction mixture wasmixed at 750 rpm. The reactor was pre-pressurized to 1000 psig in H₂followed by ramping to 250° C. (480° F.) in 40 min. After reaction atthe temperature for 2.5 hrs, the reactor temperature was further rampedup to 343° C. (650° F.) in 70 min followed by 2 hr reaction. Thesulfiding mixture was then quenched to RT.

Example 14

Experiments were carried out for HYL/HYD activity evaluation of thesulfided catalyst prepared from the catalyst precursor of Example 13.

For HYL activity evaluation, 23.81 g of diphenylether was charged atroom temperature (RT) into the reactor containing the sulfided catalyst.The reactor was sealed after purging in H₂ for 10 min. The reactionmixture was mixed at 750 rpm. The reactor was pressurized to 1000 psigin H₂ at RT followed by ramping to a reaction temperature of 382° C.(720° F.) in 2 hrs at a constant heating rate. The reactor pressure atthe reaction temperature was kept at 1800 psig. After reacting for ½ hrat 382° C., the reactor was quenched to below 100° C. in ˜2 min bycirculating cooling water. The reaction mixture was recovered from thereactor and filtered through 0.8 μm filter paper to collect a spentcatalyst for analysis/characterization.

For the HYD activity evaluation, the above experiment was repeated butwith 5.46 g of benzene as the reaction feed. The spent catalyst wascollected and characterized after reactions.

Table 16 shows the HDS and HDN activity data for the MMS catalystprepared from a hydroxide catalyst precursor. The data confirm that inthe optimum compositional range HDS and HDN activities are the highest.

TABLE 16 Ni, Mo, W HYL activity HYD activity (mol-%) (hr⁻¹ mol⁻¹) × 10³(hr⁻¹ mol⁻¹) × 10² 55, 14, 31 1.6 2.6

Example 15

Experiments were carried out for HDS/HDN activity evaluation of thesulfided catalyst prepared from the catalyst precursor of Example 13.For the evaluation, 120 g of Heavy Coker Gas Oil feed was charged at RTinto the reactor containing the sulfided catalyst. The reactor wassealed after purging in H₂ for 10 min. The reaction mixture was mixed at750 rpm. The reactor was pressurized to 1000 psig in H₂ at RT followedby ramping to a reaction temperature of 382° C. (720° F.) in 2 hrs at aconstant heating rate. The reactor pressure at the reaction temperaturewas ˜1800 psig. After reacting for ½ hr at 382° C., the reactor wasquenched to below 100° C. in ˜2 min by circulating cooling water. Thereaction mixture was recovered from the reactor and filtered through 0.8μm filter paper to collect spent catalyst for analyses andcharacterization. It was noted that the surface area of the spentcatalyst was only about half of the catalyst prepared from anorganometallic starting material (e.g., Molyvan A, cyclopentadienyltungsten dihydride, and nickel naphthenate). For a fair comparison, HDSand HDN activities were normalized by surface area and Ni surface/bulkconcentration ratio. The results shown in Table 17 provide a comparisonof the MMS catalyst prepared from a hydroxide catalyst precursor ofExample 13 to the MMS catalyst prepared from organo-metallic startingmaterials of a similar composition (55 mol-% Ni, 14 mol-% Mo and 31mol-% W

TABLE 17 Ni surface/ HDS HDN Normalized Normalized Surface bulk activity(g activity g HDS HDN Catalyst area concentration feed hr⁻¹/g feedhr⁻¹/g activity (g activity (g type m²/g ratio catalyst) × 10² catalyst)× 10² feed hr⁻¹ m⁻²) feed hr⁻¹ m⁻²) Example 13 40 0.80 3.3 0.8 10.3 2.5Organo- 74 0.77 5.8 1.3 10.2 2.3 metallic feed

Example 16

Experiments were carried out according to previously describedprocedures for HDS/HDN activity evaluation of different MMS catalystswith different transition metal percentages in hydrotreating of a HeavyVacuum Gas Oil feed. A hydroxide catalyst precursor prepared using themethod in the Example 13 was sulfided in a fixed bed reactor followingthe previously described procedure. The activity test results are asshown in Tables 18. For the catalysts having compositions within theoptimum range, the HDN and HDS activities are the highest. The HDN andHDS reaction rate constants were calculated assuming first orderkinetics on liquid weight hourly space velocity (LHSV) basis.

TABLE 18 Catalyst combination (Ni, Mo, W HDS activity mol-%) (hr⁻¹) HDNactivity on (hr⁻¹) 46, 8, 46 7.5 Nitrogen below detection  52, 14, 347.2 11.4 55, 5, 40 8.6 7.3 56, 9, 35 8.5 nitrogen below detection 58, 5,37 10.6 8.9 59, 8, 33 9.0 nitrogen below detection 59, 7, 34 9.0nitrogen below detection 61, 6, 33 8.5 nitrogen below detection 64, 8,28 9.0 8.2 65, 7, 28 10.0 Nitrogen below detection 70, 7, 23 8.3 8.1

Example 17

Experiments were carried out according to previously describedprocedures for HDS/HDN activity evaluation of different MMS catalystswith different transition metal percentages in hydrotreating of a HeavyVacuum Gas Oil feed. A hydroxide catalyst precursor prepared using themethod in the Example 13 was sulfided in a fixed bed reactor followingpreviously described procedure. The results, as shown in Table 19,indicate relatively low HDN activities for MMS catalysts withcompositions outside the optimal transition metal range. The HDS and HDNreaction rate constants were calculated assuming first order kinetics onliquid weight hourly space velocity (LHSV) basis.

TABLE 19 Catalyst combination HDS activity HDN activity (Ni, Mo, Wmol-%) (hr⁻¹) (hr⁻¹) 78, 11, 11 5.1 3.5 67, 20, 13 5.6 2.8 68, 23, 9 6.1 4.0

Example 18

Experiments were carried out according to previously describedprocedures for HDS/HDN activity evaluation of different MMS catalystswith different transition metal percentages in hydrotreating of a HeavyVacuum Gas Oil feed. A hydroxide catalyst precursor prepared using themethod in the Example 13 was sulfided in a fixed bed reactor followingthe previously described procedure. The activity test results are asshown in Table 20. Nickel/tungsten bimetallic catalyst has highhydrogenation activity:

TABLE 20 Catalyst combination HDS activity HDN activity (Ni, Mo, Wmol-%) (hr⁻¹) (hr⁻¹) 50:0:50 7.34 Nitrogen below detection

Example 19

Experiments were carried out according to previously describedprocedures for HDS/HDN activity evaluation of different MMS catalystswith different transition metal percentages in hydrotreating of a HeavyVacuum Gas Oil feed. A hydroxide catalyst precursor prepared using themethod in the Example 13 was sulfided in a fixed bed reactor followingthe previously described procedure. The activity test results are asshown in Table 21. Nickel/molybdenum bimetallic catalyst has relativelypoor hydrogenation activity.

TABLE 21 Catalyst combination HDS activity HDN activity (Ni, Mo, Wmol-%) (hr⁻¹) (hr⁻¹) 52, 48, 0 5.6 4.0 69, 31, 0 6.1 4.1

Example 20

The spent catalysts from the previous Examples were characterized by XRDand TEM.

FIG. 4 shows the XRD pattern of a spent catalyst with 50 mol-% Ni, 25mol-% Mo and 25 mol-% W, and FIG. 5 shows the XRD pattern of the spentMMS catalyst with 55 mol-% Ni, 14 mol-% Mo and 31 mol-% W, with peakscorresponding to the crystalline Ni₃S₂ phase. FIG. 6 shows the XRDpattern of a spent MMS catalyst with a sub-optimal composition (10 mol-%Ni, 45 mol-% Mo and 45 mol-% W.

FIG. 7 shows the TEM image of the spent MMS catalyst with 50 mol-% Ni,25 mol-% Mo and 25 mol-% W. The image clearly shows the presence oflarge crystalline Ni₉S₈ and Ni₃S₂. FIG. 8 is another TEM image of thisspent MMS catalyst, showing nano-particles of nickel sulfide. FIG. 9 isa TEM image of this spent MMS catalyst, showing that molybdenum tungstensulfide envelops the nickel sulfide consisting predominantly of Ni₃S₂ inthis particular case. The curvature of molybdenum tungsten sulfidelayers conforms to that of the nickel sulfide particle. FIG. 10 is a TEMimage of a spent MMS catalyst with a composition outside the optimumrange(10 mol-% Ni, 45 mol-% Mo and 45 mol-% W)There is no detectableNi₃S₂ in the image.

Tables 22 and 23 show the stacking degree data for nickel molybdenumsulfide particles, nickel tungsten sulfide particles, and nickelmolybdenum tungsten sulfide particles as well as size of slabs Thestacking degree and particle dimensions are estimated by Scherrerequation using FWHM at 14.4° and 58.3° respectively. For a nickelmolybdenum sulfide catalyst without tungsten, the stacking degreeincreased from 4 to 8 by increasing the nickel-to-m molybdenum ratiofrom 0.2 to 4.4. By contrast, for MMS catalysts that contain tungsten,the stacking degree remained at ˜3-5 and the individual slab sizesremained at about 30-45 Å in a wide compositional range. The resultsillustrate the impact of tungsten on the structure of MMS catalysts.

TABLE 22 Ni, Mo, W Stacking [110] Ni, Mo, W Stacking [110] (mol-%)degree dimension (Å) (mol-%) degree dimension (Å) 17, 83, 0 4.2 37.3 17,0, 83 4.3 32.1 50, 50, 0 3.9 42.7 50, 0, 50 3.9 37.7 64, 36, 0 5.3 40.364, 0, 36 3.9 36.3 81, 19, 0 8.4 59.7 81, 0, 19 5.1 43.9

TABLE 23 Ni, Mo, W Stacking [110] Ni, Mo, W Stacking [110] (mol-%)degree dimension (Å) (mol-%) degree dimension (Å) 10, 45, 45 3.2 33.760:20:20 4.8 43.3 20, 40, 40 3.5 36.1 64, 17, 17 4.9 42.2 33, 33, 33 4.440.8 55:14:31 4.1 44.7 50, 25, 25 4.5 42.2 55:31:14 4.6 45.3

Example 21

XPS data of the spent catalysts from the previous Examples were analyzedto determine the Ni, Mo and W surface concentration at various bulknickel, molybdenum and tungsten concentrations. It is believed thatwithin the optimal metal composition range, the catalyst surface isenriched with W. In addition, the presence of tungsten in molybdenumtungsten sulfide promotes the dispersion of NiS_(x) nano-particles onthe surface.

FIG. 11 is a graph comparing the ratio of Ni, W surface to bulkconcentration at different nickel, molybdenum and tungsten compositions.

Example 22

Freshly prepared catalysts and spent catalysts were examined andanalysed using the BET method. BET surface areas and pore volumes offreshly prepared catalysts and spent catalysts (after hydrotreatingHeavy Coker Gas Oil) were measured after a standard pretreatment at 350°C. in N₂ for 12 hr.

FIG. 12 is a graph comparing the BET surface areas of freshly preparedcatalysts and spent catalysts (after hydrotreating Heavy Coker Gas Oilfeed) at varying transition metal compositions. FIG. 13 is a graphcomparing the pore volumes of freshly prepared catalysts and spentcatalysts (after hydrotreating Heavy Coker Gas Oil feed) at varyingtransition metal compositions. For the catalysts having a transitionmetal composition outside the optimal range, e.g., 10 mol-% Ni, 45 mol-%Mo and 45 mol-% W, the BET surface area decreased almost an order ofmagnitude indicating severe surface reconstruction. For catalysts havinghigher Ni:Mo:W molar ratios, e.g., above 1:1:1, the surface areareduction was noticeably smaller.

FIGS. 14 and 15 are representative schemes illustrating the surfacestructure of a catalyst having a nickel, molybdenum and tungstencomposition within the optimal range (e.g., 50 mol-% Ni, 25 mol-% Mo and25 mol-% W (on a transition metal basis), and outside the optimal range(e.g., 10 mol-% Ni, 45 mol-% Mo and 45 mol-% W (on a transition metalbasis), respectively.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the following specification andattached claims are approximations that can vary depending upon thedesired properties sought to be obtained by the present invention. It isnoted that, as used in this specification and the appended claims, thesingular forms “a,” “an,” and “the,” include plural references unlessexpressly and unequivocally limited to one referent. As used herein, theterm “include” and its grammatical variants are intended to benon-limiting, such that recitation of items in a list is not to theexclusion of other like items that can be substituted or added to thelisted items.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. The patentable scope is defined bythe claims, and can include other examples that occur to those skilledin the art. Such other examples are intended to be within the scope ofthe claims if they have structural elements that do not differ from theliteral language of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims. All citations referred herein are expressly incorporatedherein by reference.

1. A self-supported mixed metal sulfide (MMS) catalyst comprisingmolybdenum sulfide, nickel sulfide, and tungsten sulfide, wherein thecatalyst is characterized as having an HDN reaction rate constant of atleast 100 g feed hr⁻¹ g catalyst ⁻¹ assuming first order kinetics, andan HDS reaction rate constant of at least 550 g feed hr⁻¹ g catalyst ⁻¹assuming first order kinetics in hydrotreating of a Heavy Coker Gas Oilas a feedstock with properties indicated in Table A and under processconditions as indicated in Table E.
 2. The self-supported MMS catalystof claim 1, wherein the catalyst is characterized as having an HDNreaction rate constant of at least 4 hr⁻¹ assuming first order kinetics,and an HDS reaction rate constant of at least 5 hr⁻¹, assuming firstorder kinetics in hydrotreating of a Heavy Vacuum Gas Oil as a feedstockwith properties indicated in Table B and under process conditions asindicated in Table F.
 3. The self-supported MMS catalyst of claim 1,wherein the catalyst is characterized as having an HYD reaction rateconstant and an HYL reaction rate constant of at least 10% higher thanthe rate constants of a catalyst comprising nickel sulfide andmolybdenum sulfide, or a catalyst comprising nickel sulfide and tungstensulfide, when compared on same metal molar basis in hydrotreating adiphenylether as a feedstock under process conditions as indicated inTable C.
 4. The self-supported MMS catalyst of claim 3, wherein the HYDreaction rate constant and the HYL reaction rate constant each is atleast 15% higher than the respective rate constant of a catalystcomprising nickel sulfide and molybdenum sulfide, or a catalystcomprising nickel sulfide and tungsten sulfide, when compared on thesame metal molar basis in hydrotreating of a diphenylether as afeedstock under process conditions as indicated in Table D.
 5. Theself-supported MMS catalyst of claim 1, wherein the catalyst ischaracterized as having a multi-phased structure comprising five phases:a molybdenum sulfide phase, a tungsten sulfide phase, a molybdenumtungsten sulfide phase, an active nickel phase, and a nickel sulfidephase.
 6. The self-supported MMS catalyst of claim 5, wherein themolybdenum tungsten sulfide phase comprises at least a layer whichcontains at least one of: a) molybdenum sulfide and tungsten sulfide; b)tungsten isomorphously substituted into molybdenum sulfide as individualatoms or as tungsten sulfide domains; c) molybdenum isomorphouslysubstituted into tungsten sulfide as individual atoms or as molybdenumsulfide domains; and d) mixtures thereof.
 7. The self-supported MMScatalyst of claim 6, wherein the molybdenum sulfide and tungsten sulfidephase comprises 1 to 6 layers.
 8. The self-supported MMS catalyst ofclaim 6, wherein the at least a layer comprises tungsten isomorphouslysubstituted into molybdenum sulfide as individual atoms forming anintralayer atomic mixture.
 9. The self-supported MMS catalyst of claim6, wherein the at least a layer comprises tungsten isomorphouslysubstituted into molybdenum sulfide as tungsten domains.
 10. Theself-supported MMS catalyst of claim 6, wherein the at least a layercomprises molybdenum isomorphously substituted into tungsten sulfide asindividual atoms forming an intralayer atomic mixture.
 11. Theself-supported MMS catalyst of claim 6, wherein the at least a layercomprises molybdenum isomorphously substituted into tungsten sulfide asmolybdenum domains
 12. The self-supported MMS catalyst of claim 6,wherein the surface of the molybdenum tungsten sulfide phase exhibits atleast a 20% higher molybdenum-to-tungsten ratio than the bulk of themolybdenum tungsten sulfide phase.
 13. The self-supported MMS catalystof claim 6, wherein the at least a layer comprises mixtures ofindividual domains of tungsten sulfide and molybdenum sulfide.
 14. Theself-supported MMS catalyst of claim 5, wherein the active nickel phasecomprises at least one of atomic nickel and reduced nickel substitutedinto the molybdenum tungsten sulfide phase.
 15. The self-supported MMScatalyst of claim 5, wherein the active nickel phase comprises at leastone of atomic nickel and reduced nickel decorating the edges of themolybdenum tungsten sulfide phase.
 16. The self-supported MMS catalystof claim 5, wherein the active nickel phase comprises NiS_(X)nanoparticles dispersed onto the molybdenum tungsten sulfide phase ordecorating the molybdenum tungsten sulfide phase.
 17. The self-supportedMMS catalyst of claim 5, wherein the nickel sulfide phase comprisesslabs of Ni₉S₈ and Ni₃S₂ layers.
 18. The self-supported MMS catalyst ofclaim 17, wherein the molybdenum tungsten sulfide phase envelopes theslabs of Ni₉S₈ and Ni₃S₂ layers.
 19. The self-supported MMS catalyst ofclaim 5, wherein the nickel sulfide phase serves as support for themolybdenum tungsten sulfide phase.
 20. The self-supported MMS catalystof claim 5, wherein the nickel sulfide phase stabilizes dispersion ofthe active nickel phase onto the molybdenum tungsten sulfide phase. 21.The self-supported MMS catalyst of claim 5, wherein the catalyst ischaracterized by an X-ray diffraction pattern showing peakscorresponding to MoS₂ phase and WS₂ phase.
 22. The self-supported MMScatalyst of claim 5, wherein the catalyst is characterized by an X-raydiffraction pattern showing peaks corresponding to Ni₃S₂ phase.
 23. Theself-supported MMS catalyst of claim 5, wherein the catalyst ischaracterized by TEM image showing lattice fringes on nickel sulfidecrystals of 4.60±0.5 Å and 2.87±0.5 Å.
 24. The self-supported MMScatalyst of claim 1, wherein the catalyst has a BET surface area of atleast 20 m²/g and a pore volume of at least 0.05 cm³/g.
 25. Theself-supported MMS catalyst of claim 24, wherein the catalyst has a BETsurface area of at least 40 m²/g and a pore volume of at least 0.05cm³/g.
 26. The self-supported MMS catalyst of claim 1, wherein thecatalyst after hydrotreating a Heavy Coker Gas Oil for at least 0.5 hrs,has a surface area reduction of less than 80%.
 27. The self-supportedMMS catalyst of claim 1, wherein the catalyst has a Ni surfaceconcentration/Ni bulk concentration ratio of greater than 0.4 ascharacterized by XPS.
 28. The self-supported MMS catalyst of claim 27,wherein the catalyst has a Ni surface concentration/Ni bulkconcentration ratio of greater than 0.5 as characterized by XPS.
 29. Theself-supported MMS catalyst of claim 1, wherein the catalyst has a Wsurface concentration/W bulk concentration ratio of greater than 0.3 ascharacterized by XPS.
 30. The self-supported MMS catalyst of claim 29,wherein the catalyst has a W surface concentration/W bulk concentrationratio of greater than 0.4 as characterized by XPS.
 31. Theself-supported MMS catalyst of claim 1, wherein the catalyst comprisesmolybdenum sulfide, nickel sulfide, and tungsten sulfide with molarratios of metal components Ni:Mo:W in a region defined by five pointsABCDE of a ternary phase diagram, and wherein the five points ABCDE aredefined as: A (Ni=0.72, Mo=0.00, W=0.28), B (Ni=0.25, Mo=0.00, W=0.75),C (Ni=0.25, Mo=0.25, W=0.50), D (Ni=0.60, Mo=0.25, W=0.15), E (Ni=0.72,Mo=0.13, W=0.15).
 32. The self-supported MMS catalyst of claim 1,wherein the catalyst comprises molybdenum sulfide, nickel sulfide, andtungsten sulfide with molar ratios of metal components Ni:Mo:W in aregion defined by six points ABCDEF of a ternary phase diagram, andwherein the six points ABCDEF are defined as: A(Ni=0.67,Mo=0.00,W=0.33), B (Ni=0.67, Mo=0.10, W=0.23), C (Ni=0.60,Mo=0.15, W=0.25), D (Ni=0.52, Mo=0.15, W=0.33), E (Ni=0.52, Mo=0.06,W=0.42), F (Ni=0.58, Mo=0.0, W=0.42).
 33. The self-supported MMScatalyst of claim 1, wherein the catalyst comprises molybdenum sulfide,nickel sulfide, and tungsten sulfide with molar ratios of metalcomponents Ni:Mo:W in a region defined by four points ABCD of a ternaryphase diagram, and wherein the four points ABCD are defined as:A(Ni=0.67,Mo=0.00,W=0.33), B(Ni=0.58, Mo=0.0, W=0.42), C(Ni=0.52,Mo=0.15, W=0.33), D(Ni=0.60, Mo=0.15, W=0.25).